Chemistry

HCL

Hydrochloric acid

H2SO4

Sulfuric acid

CO2

Carbon Dioxide

H2O

Water

NaCl

Sodium Chloride

CO3

Carbonate

SO4

Sulfate

NH4

Ammonium

Neutral

pH 7

Acids

Corrosive, sour

Bases

Caustic, bitter - soluble base = Alkali (or pH 8 +)

pH

Potential hydrogen atoms reflecting the acidity or basicity of a substance.

Law of conservation of mass

Matter can be neither created nor destroyed during a chemical reaction.

Endothermic Reaction

Energy is absorbed into the surroundings, temperature decreases.

Exothermic reactions

Energy is released into the surroundings, temperature increases.

Aerobic Respiration

Glucose + oxygen → carbon dioxide + water + energy

Anaerobic respiration

Glucose → lactic acid + energy

Corrosion reaction

Metal + acid → salt + hydrogen gas

Neutralisation Reaction

Acid + Base → salt + water

OR

Acid + carbonate → salt + water + carbon dioxide

Combustion reaction

Fuel + oxygen → carbon dioxide + water + energy

Photosynthesis

Carbon dioxide + water (+ light energy/chlorophyll) → glucose + oxygen

Use of energy in a chemical reaction

Energy is required to activate a chemical reaction

5 things to speed up a chemical reaction

• catalyst

• increase surface area

• increase quantities of reactants

• increase energy input (heat)

• agitation

Balancing equations

3Fe + 2O2 → Fe3O4

Atomic Number

Top number on periodic table - Number of protons in an atom

Atomic mass

Bottom number - Number of protons + neutrons

Isotope

An atom of the same element with a different number of neutrons.

Unstable Isotopes

The larger the difference between protons and neutrons, the more unstable the atom is.

Alpha radiation

The ejection of 2 protons and 2 neutrons (a helium atom)

causes damage if ingested or inhaled.

Beta Radiation

A neutron splits into a proton and electron, electron is ejected and so proton is gained.

Cannot penetrate plastic, wood or rubber.

Gamma radiation

The emission of a photon (energy packet) after alpha or beta particles have been ejected.

Only lead or concrete stop penetration.

Half life

The average time it takes for the nuclei in a sample to decay by half the original amount is the half life.